Advances in medical diagnostic imaging have greatly increased the utility of many radiographic and cardiologic procedures it is expected that greater numbers of patients will undergo these procedures in the years to come. Unfortunately, these procedures continue to rely on iodinated contrast (such as Iopamiron 370, iodixanol, etc.) for identification of vascular structures and no viable alternatives have yet emerged. For example, such agents are often injected in the brain arteries during brain arterial procedures.
While advances have been made in the design and composition of contrast, these agents still carry a risk of renal injury and account for a significant number of cases of hospital-acquired renal failure (Gleeson and Bulugahapitiya Am J Roentgenol 2004; 183:1673-1689; Nash et al. Am J Kidney Dis 2002; 39:930-936). Contrast-induced nephropathy (CIN), defined as evidence of renal injury or dysfunction following exposure to contrast agents for imaging studies is a common and potentially serious complication. The risk of CIN is highest in patients with underlying kidney disease or injury, but multiple other risk factors have been identified including intra-arterial administration of contrast, higher contrast volumes (>100 mL), diabetes and underlying cardiac disease. CIN has an incidence of 15% of cases performed in the brain vasculature, and it carries a mortality risk of 0.8-1%.
No adjunctive medical or mechanical treatment has been proved to be efficacious in reducing the risk of CIN. In principal, removal of contrast directly from whole blood could significantly reduce the risk of CIN particularly if it could be done rapidly and with higher efficiency, before significant exposure to the kidneys could take place. However, current clinical techniques to prevent nephropathy are only medical and are notoriously inefficacious. For example, United States Patent Application Publication No. 2002-0099254 (Movahed et al.) proposes a method to remove contrast agent from vessels of the heart that involves filtration using a membrane that catches everything but red blood cells, centrifugation to remove red blood cells, or suctioning off portions of the patient's blood. However, late application of such limited efficacy blood purification, such as using traditional hemodialysis is ineffective (Frank Clin Nephrol 2003:60; 176-182). Accordingly, more effective technologies for minimizing the risk of contrast-induced nephropathy are desirable.